The present invention is related to the field of data storage systems.
Data storage systems may utilize a file-based representation of block-oriented storage objects that are exposed to external users, such as host computers accessing the data storage system via a network. For example, a logical unit of storage or LUN is a block-oriented storage object visible as a block-oriented storage device to a host computer. Internally, however, the storage system may map the LUN into a file of an internal file system, and then manage access and other aspects of the LUN by corresponding operations on the mapped file. This organization can help enhance efficiency of processing storage operations. Additionally, in current systems employing virtual computing technology, units of virtualized storage for virtual machines may be represented as files of a distributed file system used by a host computer and one or more network-attached storage (NAS) systems. Within a host, accessing a virtualized storage unit requires a mapping to a file of the distributed file system, and within the storage system the file is mapped to underlying physical storage that contains the data of the virtualized storage unit. This mapping may be a multi-level mapping that may include use of a separate internal file system. Both the distributed file system and the internal file system may be described as “hosting” the virtualized storage units.